Annual

Annual, biennial or perennial?

Plants are often grouped by how long they live. An annual packs its entire life into a single year: it germinates, grows, flowers, sets seed and then dies, all in one season. A perennial lives for several years, dying back and regrowing each spring. A biennial sits in between — it grows leaves and roots in its first year, then flowers, seeds and dies in its second.

For a beginner, the practical message is simple. Annuals are a fresh start every spring, so you sow them, crop them and clear them within the year. That sounds like more work, but it's also forgiving: a poor result is gone by autumn, and you get a clean go at it next season.

Most veg are annuals

The bulk of what you'll grow in a UK veg patch are annuals. Tomatoes, courgettes, runner beans, French beans, peas, lettuce, salad leaves, sweetcorn, pumpkins and most squash all run from seed to harvest to dead plant within one season. You sow them in spring, usually after the last frost for the tender ones, and pull them out once they've finished cropping in autumn.

This is why a veg plot looks busy and ever-changing. Because annuals don't come back, you replant each year — which is also your chance to rotate crops around the beds and refresh the soil with compost.

Annual herbs

Some of the most useful kitchen herbs are annuals, and it's worth knowing which, because they won't survive the winter to crop again:

• Basil — a true tender annual that hates the cold. Grow it on a warm windowsill or in a greenhouse and resow each year.
• Coriander — quick to grow but quick to flower, especially in hot, dry spells; it bolts, sets seed and is done.
• Dill — another fast annual that runs to seed within the season.

Sowing a fresh batch every few weeks — known as successional sowing — keeps annual herbs and salads coming, rather than getting one big flush that flowers and finishes all at once.

Watch out for early bolting

Annuals are programmed to flower and set seed, but stress can rush them into it before you've had your crop. When lettuce, spinach or coriander runs to flower early — usually triggered by heat, drought or a check to growth — we call it bolting. The leaves turn bitter and tough as the plant switches its energy to seed.

You can't stop an annual flowering for ever, but steady watering, a little shade in high summer and regular picking all hold it off. And once an annual has gone over, that's simply its life cycle finishing on time — pull it out, add it to the heap and sow the next thing.

Ready to plan a year of sowings? Our guide to starting a vegetable garden walks you through what to sow and when.